BACKGROUND: Lifestyle determines the amount of exposure to environmental carcinogens/mutagens. We examined the relationship between various lifestyle factors and the urinary level of mutagens, which reflects both exposure dose and metabolism of these carcinogens/ mutagens. METHODS: Twenty-four-hour urine specimens obtained from 69 males were subjected to blue rayon extraction, after which the elutions were fractionated by carboxymethyl cellulose column chromatography. The mutagens were measured by using an S9-mediated Salmonella mutagenicity test. The subjects were classified into three groups according to their total scores on a questionnaire regarding eight health practices: cigarette smoking, alcohol drinking, nutritional balance, eating breakfast, sleeping hours, working hours, physical exercise, and mental stress. RESULTS: Compared with those with "poor" health practice, subjects with "good" health practice showed a significantly lower urinary level of mutagens in all chromatography fractions, as well as in the acid- and alkali-elutable fractions. Cigarette smoking and nutritional balance were the most highly correlated factors. CONCLUSIONS: Our findings show that poor health practices increase the urinary level of mutagens, suggesting that a healthy lifestyle reduces exposure to carcinogens/ mutagens and may reduce cancer risk.

Adult↗

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Healthy lifestyles are associated with higher lymphokine-activated killer cell activity.

BACKGROUND: To investigate the association between lifestyle factors and immune responses to tumors, we determined lymphokine-activated killer (LAK) cell activity and proportions of lymphocyte subsets in 54 healthy males. METHODS: LAK cell activity was determined by 51Cr release assay. The proportions of natural killer cells (CD3-16+56-, CD3-16-56+ or CD3-16+56+ cells), helper/ inducer T cells (CD4+8-), and cytotoxic/suppressor T cells (CD4-8+) in lymphocytes were also determined by flow cytometry. Subjects were classified into two groups, good or poor overall lifestyle, according to their answers on a questionnaire regarding eight health practices (cigarette smoking, alcohol consumption, physical exercise, mental stress, sleeping pattern, nutritional balance, eating breakfast, working pattern). RESULTS: Subjects with good health practices regarding smoking showed significantly higher LAK cell activity. They also showed a significantly higher proportion of natural killer cells and a lower proportion of helper/inducer T cells. LAK cells activity was significantly higher in subjects with a good overall lifestyle than in those with a poor overall lifestyle after controlling for the effects of smoking. There were no significant differences in the proportions of lymphocyte subsets between the two lifestyle groups. CONCLUSIONS: Lifestyle factors are associated with LAK cell activity and the proportion of lymphocyte subsets.

Adult↗

PubMedDate not supplied

Type A and Type B behaviors, work stressors, and social support at work.

BACKGROUND: How Type A personality is related to the stress process has been investigated. However, in the occupational health field, stressful aspects of the work environment for Type A or B workers have not been fully revealed. METHODS: In the present study, using signal detection analysis, we analyzed data concerning work stressors and social support (SS) at work among Japanese white-collar workers (n = 560) and identified the respective aspects of work that are stressful for Type A and B workers. We also evaluated the interactions of SS at work and stressor variables among Type A and B workers, individually. RESULTS: Except for one significant predictor, i.e., being unable to learn new things at work, the significant predictors of mental stress were generally quite different for Type A and B workers. Specifically, SS from management was a cause of mental stress for certain groups of Type A workers. CONCLUSIONS: It was revealed that the stressful aspects of work environment varied markedly in accord with the Type A vs Type B personality status of the subjects. The results also implied that even support from management can be stressful for Type A workers who had heavy workloads. The present study used specific measures sensitive to individual stressors and identified specific subgroups with the same work stressors. The findings provide information that is useful for stress reduction intervention.

Adult↗

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Sister-chromatid exchanges and cell-cycle kinetics in human lymphocyte cultures exposed to alkylating mutagens: apparent deformity in dose-response relationships.

Experiments have been carried out using human whole-blood cultures to determine the effects of sampling times and of the duration of 5-bromodeoxyuridine (BrdUrd) treatment before fixation on sister-chromatid exchange (SCE) frequencies following exposure to mitomycin C (MMC). Cells were pulse treated for 1 h with 3 X 10(-6) M MMC at G1, and then sampled at 4-h intervals up to 88 h after stimulation of cultures with phytohemagglutinin (PHA). Results showed that this MMC treatment induced a 5-6 h proliferation delay per cell cycle, and that SCE frequencies first increased with time of fixation, peaking at 68 h, and then decreased. When cells were similarly treated with MMC, but subsequently exposed to BrdUrd for various times before fixation of cultures at 72 h, the SCE frequencies markedly increased with increasing durations of BrdUrd incubation times. These data indicate that, in mutagen-treated cultures, lymphocytes having relatively longer cell-cycle times show a higher mean frequency of SCEs. In a subsequent experiment, cells were treated for 1 h with increasing doses of MMC or 4-nitroquinoline 1-oxide (4NQO) at 0, 24, or 48 h, and then fixed at 72 h after PHA stimulation. Results showed that the optimal treatment times at which the agents could most efficiently produce SCEs were different for MMC and 4NQO, and that the dose-response curves tended to 'bend down' at very high doses; that is, treatments with very high doses induced smaller than expected numbers of SCEs. However, cells similarly treated with very high doses showed a higher, expected frequency of SCEs when sampled at 84 h, but again had a lower than expected SCE frequency when fixed at 96 h. The results indicate that there is an optimal time for sampling at which one can observe the maximum increase in SCE frequencies following mutagen exposure, and strongly suggest that the higher the dose, the later the optimal sampling time. Because of the apparent deformity of dose-response curves obtained after various treatments and sampling times, it seems necessary that extra fixation-time points be included in test protocols so as to avoid false negatives or confirm possible positives.

4-Nitroquinoline-1-oxide↗

PubMedDate not supplied

Involvement of calmodulin in platelet reaction.

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Arachidonic Acid↗

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Effects of diesel exhaust particles on chromosome aberration, sister chromatid exchange and morphological transformation in cultured mammalian cells.

The ability of diesel exhaust particles (diesel tar) from light-duty (LD) and heavy-duty (HD) engines to induce chromosome aberrations, sister chromatid exchanges (SCEs) and morphological transformations is examined. Chinese hamster V79 cells were treated with LD and HD diesel tar for 3 h in order to analyze chromosome aberrations and SCEs. BALB/c 3T3 cells were used for the morphological transformation test. LD tar induced significant numbers of chromosome aberrations, whereas HD did not. Both LD and HD samples increased the number of SCEs in a dose-dependent fashion, with LD being more potent. In the transformation test, LD tar also induced a significant number of Type III foci, while HD was only weakly active. The transformed cells isolated from these Type III foci produced tumors when injected into nude mice. These results show that LD possesses clear clastogenic and transforming capabilities but that HD is weaker in this regard.

Animals↗